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BonoboMonikerExtender
Libbonobo Reference Manual
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BonoboMonikerExtender

Name

BonoboMonikerExtender -- A way to extend arbitary monikers

Synopsis


#define     BONOBO_MONIKER_EXTENDER_TYPE
struct      BonoboMonikerExtender;
Bonobo_Unknown (*BonoboMonikerExtenderFn)   (BonoboMonikerExtender *extender,
                                             const Bonobo_Moniker parent,
                                             const Bonobo_ResolveOptions *options,
                                             const CORBA_char *display_name,
                                             const CORBA_char *requested_interface,
                                             CORBA_Environment *ev);
typedef     BonoboMonikerExtenderClass;
BonoboMonikerExtender* bonobo_moniker_extender_new
                                            (BonoboMonikerExtenderFn resolve,
                                             gpointer data);
Bonobo_MonikerExtender bonobo_moniker_find_extender
                                            (const gchar *name,
                                             const gchar *interface,
                                             CORBA_Environment *opt_ev);
Bonobo_Unknown bonobo_moniker_use_extender  (const gchar *extender_oafiid,
                                             BonoboMoniker *moniker,
                                             const Bonobo_ResolveOptions *options,
                                             const CORBA_char *requested_interface,
                                             CORBA_Environment *opt_ev);

Description

A moniker extender is used to extend the functionality of a moniker. There are two standard moniker extenders that cannot be system wide, since they use the oaf database to expand the scope of a moniker to arbitrarily many interfaces. These are invoked explicitely by monikers implementing the stream interface in the following way:

Example 1. Explicit Stream extender usage example

Bonobo_Unknown
example_moniker_resolve (BonoboMoniker               *moniker,
 const Bonobo_ResolveOptions *options,
 const CORBA_char            *requested_interface,
 CORBA_Environment           *ev)
{
if (!strcmp (requested_interface, "IDL:Bonobo/Stream:1.0"))
return handle_stream (moniker, options, ev);
else
return bonobo_moniker_use_extender (
"OAFIID:Bonobo_MonikerExtender_stream",
moniker, options, requested_interface, ev);
}
The moniker extender essentialy resolves 'moniker' against stream and my some means ( not known when the moniker was written ) converts this to a new exotic interface - via. the PersistStream interface.

All standard moniker extenders are registered by adding a fragment like this:

Example 2. Oaf information for an extender

<oaf_attribute name="bonobo:moniker_extender" type="stringv">
<item value="file:"/>
</oaf_attribute>
to the .oaf file. This registers the extender with the system, such that when a moniker resolve fails an extender can be found for any of the monikers with prefix specified in the "bonobo:moniker_extender" stringv.

Implementing your own extender is extremely simple, much like BonoboMonikerSimple.

Example 3. Oaf information for an extender

Bonobo_Unknown
example_extender_resolve (BonoboMonikerExtender *extender,
  const Bonobo_Moniker   m,
  const Bonobo_ResolveOptions *options,
  const CORBA_char      *display_name,
  const CORBA_char      *requested_interface,
  CORBA_Environment     *ev)
{
... resolve 'm' against an interface we know it supports ...
... then use that interface to provide requested_interface ...
}
It is registered again in much the same way in your factory:

Example 4. Creating a new simple moniker

static BonoboObject *
bonobo_std_moniker_factory (BonoboGenericFactory *this,
    const char           *object_id,
    void                 *data)
{
g_return_val_if_fail (object_id != NULL, NULL);

if (!strcmp (object_id, "OAFIID:Bonobo_MonikerExtender_file"))
return BONOBO_OBJECT (bonobo_moniker_extender_new (
example_extender_resolve, NULL));
else
return NULL;
}

Details

BONOBO_MONIKER_EXTENDER_TYPE

#define BONOBO_MONIKER_EXTENDER_TYPE        BONOBO_TYPE_MONIKER_EXTENDER /* deprecated, you should use BONOBO_TYPE_MONIKER_EXTENDER */

struct BonoboMonikerExtender

struct BonoboMonikerExtender {
        BonoboObject           object;
BonoboMonikerExtenderFn resolve;
gpointer                data;
};

BonoboMonikerExtenderFn ()

Bonobo_Unknown (*BonoboMonikerExtenderFn)   (BonoboMonikerExtender *extender,
                                             const Bonobo_Moniker parent,
                                             const Bonobo_ResolveOptions *options,
                                             const CORBA_char *display_name,
                                             const CORBA_char *requested_interface,
                                             CORBA_Environment *ev);

extender : 
parent : 
options : 
display_name : 
requested_interface : 
ev : 
Returns : 

BonoboMonikerExtenderClass

typedef struct {
BonoboObjectClass      parent_class;

POA_Bonobo_MonikerExtender__epv epv;

BonoboMonikerExtenderFn resolve;
} BonoboMonikerExtenderClass;

bonobo_moniker_extender_new ()

BonoboMonikerExtender* bonobo_moniker_extender_new
                                            (BonoboMonikerExtenderFn resolve,
                                             gpointer data);

This creates a new moniker extender.

resolve : the resolve function that will be used to do the extension
data : user data to be passed back to the resolve function.
Returns : the extender object

bonobo_moniker_find_extender ()

Bonobo_MonikerExtender bonobo_moniker_find_extender
                                            (const gchar *name,
                                             const gchar *interface,
                                             CORBA_Environment *opt_ev);

This routine tries to locate an extender for our moniker by examining a registry of extenders that map new interfaces to certain moniker names.

name : the name of the moniker we want to extend eg. 'file:'
interface : the interface we want to resolve to
opt_ev : an optional corba exception environment.
Returns : an appropriate extender or CORBA_OBJECT_NIL.

bonobo_moniker_use_extender ()

Bonobo_Unknown bonobo_moniker_use_extender  (const gchar *extender_oafiid,
                                             BonoboMoniker *moniker,
                                             const Bonobo_ResolveOptions *options,
                                             const CORBA_char *requested_interface,
                                             CORBA_Environment *opt_ev);

Locates a known extender via. OAFIID; eg. OAFIID:Bonobo_Moniker_Extender_file

extender_oafiid : The IID of the extender to use
moniker : the moniker to extend
options : resolve options
requested_interface : the requested interface
opt_ev : optional corba environment
Returns : the resolved result or CORBA_OBJECT_NIL.



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